Time Thresholds for Using Pressure Reactivity Index in Neuroprognostication for Patients With Severe Traumatic Brain Injury.

BACKGROUND AND OBJECTIVES: Severe traumatic brain injury (sTBI) represents a diffuse, heterogeneous disease where therapeutic targets for optimizing clinical outcome remain unclear. Mean pressure reactivity index (PRx) values have demonstrated associations with clinical outcome in sTBI. However, the retrospective derivation of a mean value diminishes its bedside significance. We evaluated PRx temporal profiles for patients with sTBI and identified time thresholds suggesting optimal neuroprognostication. METHODS: Patients with sTBI and continuous bolt intracranial pressure monitoring were identified. Outcomes were dichotomized by disposition status ("good outcome" was denoted by home and acute rehabilitation). PRx values were obtained every minute by taking moving correlation coefficients of intracranial pressures and mean arterial pressures. Average PRx trajectories for good and poor outcome groups were calculated by extending the last daily averaged PRx value to day 18. Each patient also had smoothed PRx trajectories that were used to generate "candidate features." These "candidate features" included daily average PRx's, cumulative first-order changes in PRx and cumulative second-order changes in PRx. Changes in sensitivity over time for predicting poor outcome was then evaluated by generating penalized logistic regression models that were derived from the "candidate features" and maximized specificity. RESULTS: Among 33 patients with sTBI, 18 patients achieved good outcome and 15 patients had poor outcome. Average PRx trajectories for the good and poor outcome groups started on day 6 and consistently diverged at day 9. When targeting a specificity >83.3%, an 85% maximum sensitivity for determining poor outcome was achieved at hospital day 6. Subsequent days of PRx monitoring showed diminishing sensitivities. CONCLUSION: Our findings suggest that in a population of sTBI, PRx sensitivities for predicting poor outcome was maximized at hospital day 6. Additional study is warranted to validate this model in larger populations.

Pressure reactivity index for early neuroprognostication in poor-grade subarachnoid hemorrhage.

BACKGROUND: Pressure reactivity index (PRx) utilizes moving correlation coefficients from intracranial pressure (ICP) and mean arterial pressures to evaluate cerebral autoregulation. We evaluated patients with poor-grade subarachnoid hemorrhage (SAH), identified their PRx trajectories over time, and identified threshold time points where PRx could be used for neuroprognostication. METHODS: Patients with poor-grade SAH were identified and received continuous bolt ICP measurements. Dichotomized outcomes were based on ninety-day modified Rankin scores and disposition. Smoothed PRx trajectories for each patient were created to generate "candidate features" that looked at daily average PRx, cumulative first-order changes in PRx, and cumulative second-order changes in PRx. "Candidate features" were then used to perform penalized logistic regression analysis using poor outcome as the dependent variable. Penalized logistic regression models that maximized specificity for poor outcome were generated over several time periods and evaluated how sensitivities changed over time. RESULTS: 16 patients with poor-grade SAH were evaluated. Average PRx trajectories for the good (PRx < 0.25) and poor outcome groups (PRx > 0.5) started diverging at post-ictus day 8. When targeting specificities ≥88% for poor outcome, sensitivities for poor outcome consistently increased to >70% starting at post-ictus days 12-14 with a maximum sensitivity of 75% occurring at day 18. CONCLUSIONS: Our results suggest that by using PRx trends, early neuroprognostication in patients with SAH and poor clinical exams may start becoming apparent at post-ictus day 8 and reach adequate sensitivities by post-ictus days 12-14. Further study is required to validate this in larger poor-grade SAH populations.

Decompressive hemicraniectomy and cranioplasty using subcutaneously preserved autologous bone flaps versus synthetic implants: perioperative outcomes and cost analysis.

OBJECTIVE: It has not been well-elucidated whether there are advantages to preserving bone flaps in abdominal subcutaneous (SQ) tissue after decompressive hemicraniectomy (DHC), compared to discarding bone flaps. The authors aimed to compare perioperative outcomes and costs for patients undergoing autologous cranioplasty (AC) after DHC with the bone flap preserved in abdominal SQ tissue, and for patients undergoing synthetic cranioplasty (SC). METHODS: A retrospective review was performed of all patients undergoing DHC procedures between January 2017 and July 2021 at two tertiary care institutions. Patients were divided into two groups: those with flaps preserved in SQ tissue (SQ group), and those with the flap discarded (discarded group). Additional analysis was performed between patients undergoing AC versus SC. Primary end points included postoperative and surgical site complications. Secondary endpoints included operative costs, length of stay, and blood loss. RESULTS: A total of 248 patients who underwent DHC were included in the study, with 155 patients (62.5%) in the SQ group and 93 (37.5%) in the discarded group. Patients in the discarded group were more likely to have a diagnosis of severe TBI (57.0%), while the most prevalent diagnosis in the SQ group was malignant stroke (35.5%, p < 0.05). There were 8 (5.2%) abdominal surgical site infections and 9 (5.8%) abdominal hematomas. The AC group had a significantly higher reoperation rate (23.2% vs 12.9%, p = 0.046), with 11% attributable to abdominal reoperations. The average cost of a reoperation for an abdominal complication was $40,408.75 ± $2273. When comparing the AC group to the SC group after cranioplasty, there were no significant differences in complications or surgical site infections. There were 6 cases of significant bone resorption requiring cement supplementation or discarding of the bone flap. Increased mean operative charges were found for the SC group compared to the AC group ($72,362 vs $59,726, p < 0.001). CONCLUSIONS: Autologous bone flaps may offer a cost-effective option compared to synthetic flaps. However, when preserved in abdominal SQ tissue, they pose the risk of resorption over time as well as abdominal surgical site complications with increased reoperation rates. Further studies and methodologies such as cryopreservation of the bone flap may be beneficial to reduce costs and eliminate complications associated with abdominal SQ storage.

Cirq robotic arm-assisted transpedicular instrumentation with intraoperative navigation: technical note and case series with 714 thoracolumbar screws.

The Cirq is a surgeon-controlled robotic arm that provides a new technique for accurately placing transpedicular screws. This report aims to present a technical report and our experience with this new robotic arm combined with intraoperative navigation. Technique and workflow using the Cirq robotic arm with intraoperative navigation is described. A retrospective review was conducted of all patients undergoing elective open thoracic/lumbar fusion surgery by a single surgeon in the first year of using the novel Cirq robotic arm. Descriptive analysis of patient and operative variables was performed. A total of 84 patients underwent placement of a total 714 transpedicular screws using the Cirq robotic arm. Most (69.1%) underwent 3-6 level fusion procedures. Mean operative time was 198 min total and 28 min when adjusted per screw. There was a learning curve with operative time per screw decreasing from 32 to 25 min from the first to second half of cases (p = 0.057). There were no intraoperative screw revisions and 2.4% (2/84) required instrumentation revision and return to the operating room. The Cirq robotic arm is seamlessly incorporated into the workflow of a transpedicular fusion. Our experience with over 700 pedicle screw placements using the Cirq robot demonstrates efficacy and safety although further comparative studies are needed.

Admission Neutrophil to Lymphocyte Ratio for Predicting Outcome in Subarachnoid Hemorrhage.

PURPOSE: We sought to evaluate the relationship between admission neutrophil-to-lymphocyte ratio (NLR) and functional outcome in aneurysmal subarachnoid hemorrhage (aSAH) patients. MATERIAL AND METHODS: Consecutive patients with aSAH were treated at two tertiary stroke centers during a five-year period. Functional outcome was defined as discharge modified Rankin score dichotomized at scores 0-2 (good) vs. 3-6 (poor). RESULTS: 474 aSAH patients were evaluated with a mean NLR 8.6 (SD 8.3). In multivariable logistic regression analysis, poor functional outcome was independently associated with higher NLR, older age, poorer clinical status on admission, prehospital statin use, and vasospasm. Increasing NLR analyzed as a continuous variable was independently associated with higher odds of poor functional outcome (OR 1.03, 95%CI 1.00-1.07, p=0.05) after adjustment for potential confounders. When dichotomized using ROC curve analysis, a threshold NLR value of greater than 6.48 was independently associated with higher odds of poor functional outcome (OR 1.71, 95%CI 1.07-2.74, p=0.03) after adjustment for potential confounders. CONCLUSIONS: Higher admission NLR is an independent predictor for poor functional outcome at discharge in aSAH patients. The evaluation of anti-inflammatory targets in the future may allow for improved functional outcome after aSAH.

Abnormal neurological pupil index is associated with malignant cerebral edema after mechanical thrombectomy in large vessel occlusion patients.

BACKGROUND AND OBJECTIVES: Malignant cerebral edema (MCE) is a feared complication in patients suffering from large vessel occlusion. Variables associated with the development of MCE have not been clearly elucidated. Use of pupillometry and the neurological pupil index (NPi) as an objective measure in patients undergoing mechanical thrombectomy (MT) has not been explored. We aim to evaluate variables significantly associated with MCE in patients that undergo MT and hypothesize that abnormal NPi is associated with MCE in this population. METHODS: A retrospective analysis of patients with acute ischemic stroke who had undergone MT at our institution between 2017 and 2020 was performed. Baseline and outcome variables were collected, including NPi values from pupillometry readings of patients within 72 h after the MT. Patients were divided into two groups: MCE versus non-MCE group. A univariate and multivariate analysis was performed. RESULTS: Of 284 acute ischemic stroke patients, 64 (22.5%) developed MCE. Mean admission glucose (137 vs. 173; p < 0.0001), NIHSS on admission (17 vs. 24; p < 0.01), infarct core volume (27.9 vs. 17.9 mL; p = 0.0036), TICI score (p = 0.001), and number of passes (2.9 vs. 1.8; p < 0.0001) were significantly different between the groups. Pupillometry data was present for 64 patients (22.5%). Upon multivariate analysis, abnormal ipsilateral NPi (OR 21.80 95% CI 3.32-286.4; p = 0.007) and hemorrhagic conversion were independently associated with MCE. CONCLUSION: Abnormal NPi and hemorrhagic conversion are significantly associated with MCE in patients following MT. Further investigation is warranted to better define an association between NPi and patient outcomes in this patient population.

Increased Pulse Pressure Variability Within the First 24 Hours Leads to Poor Disposition in Subarachnoid Hemorrhage Patients.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (SAH) continues to be associated with significant morbidity and mortality despite treatment advancements. Although high blood pressure (BP) remains a significant risk factor in aneurysmal SAH and rerupture, the role of BP parameters and fluctuation in prognostication remains unclear. We sought to define how BP parameters and variability within 24 hours of hospitalization in acute-onset SAH affects patient discharge outcomes. METHODS: We retrospectively analyzed a prospectively collected cohort of SAH patients. Hourly BP parameters, including systolic BP (SBP), diastolic BP, pulse pressure (PP), and their corresponding variability (delineated by SD), were collected to investigate associations with the primary endpoint of discharge disposition. RESULTS: One hundred and seventy-four SAH patients were included in the study. On bivariate analysis, Hunt-Hess (HH) score, Fisher grade, intraventricular hemorrhage, external ventricular drain placement, and SBP and PP variability were significantly associated with a poor disposition. Poor disposition was significantly associated with age, HH score, intraventricular hemorrhage, and PP variability on multivariate analysis. PP variability remained an independent predictor for poor disposition (odds ratio 1.11, 95% confidence interval, 1.02-1.21, P = 0.02) when adjusting for potential confounders. CONCLUSIONS: Increased BP and PP variability within the first 24 hours of admission portends a poor discharge disposition for aneurysmal SAH patients.

Effect of Incisional Negative Pressure Wound Therapy vs Standard Wound Dressing on the Development of Surgical Site Infection after Spinal Surgery: A Prospective Observational Study.

BACKGROUND: Use of a closed-incisional negative pressure therapy (ci-NPT) dressing is an emerging strategy to reduce surgical site infections (SSIs) in spine surgery that lacks robust data. OBJECTIVE: To determine the impact of a ci-NPT, as compared with a standard dressing, on the development of SSIs after spine surgery. METHODS: This was a prospective observational study over a 2-yr period. Indications for surgery included degenerative disease, deformity, malignancy, and trauma. Exclusion criteria included anterior and lateral approaches to the spine, intraoperative durotomy, or use of minimally invasive techniques. SSIs up to 60 d following surgery were recorded. RESULTS: A total of 274 patients were included. SSI rate was significantly lower with ci-NPT dressing (n = 118) as compared with the standard dressing (n = 156) (3.4 vs 10.9%, P = .02). There was no statistical difference in infection rate for decompression alone procedures (4.2 vs 9.1%, P = .63), but there was a statistically significant reduction with the use of a negative-pressure dressing in cases that required instrumentation (3.2 vs 11.4%, P = .03). Patients at higher risk (instrumentation, deformity, and malignancy) had less SSIs with the use of ci-NPT, although this did not reach statistical significance. There were no complications in either group. CONCLUSION: SSI rates were significantly reduced with a ci-NPT dressing vs a standard dressing in patients who underwent spinal surgery. The higher cost of a ci-NPT dressing might be justified with instrumented cases, as well as with certain high-risk patient populations undergoing spine surgery, given the serious consequences of an infection.

The Retroauricular Incision as an Effective and Safe Alternative Incision for Decompressive Hemicraniectomy.

BACKGROUND: The reverse question mark (RQM) incision has been traditionally utilized to perform decompressive hemicraniectomies (DHC) to relieve refractory intracranial hypertension. Alternative incisions have been proposed in the literature but have not been compared directly. OBJECTIVE: To present the retroauricular (RA) incision as an alternative incision that we hypothesize will increase calvarium exposure to maximize the removal of the hemicranium and will decrease wound-related complications compared to the RQM incision. METHODS: This study is a retrospective review of all DHCs performed at our institution over a span of 34 mo, stratified based on the type of scalp incision. The surface areas of the cranial defects were calculated, normalizing to their respective skull diameters. For those patients surviving beyond 1 wk, complications were examined from both cohorts. RESULTS: A total of 63 patients in the RQM group and 43 patients in the RA group were included. The average surface area for the RA and RQM incisions was 117.0 and 107.8 cm2 (P = .0009), respectively. The ratio of average defect size to skull size for RA incision was 0.81 compared to 0.77 for the RQM group (P = .0163). Of those who survived beyond 1 wk, the absolute risk for surgical site complications was 14.0% and 8.3% for RQM and RA group (P = .5201), respectively. CONCLUSION: The RA incision provides a safe and effective alternative incision to the traditional RQM incision used for DHC. This incision affords a potentially larger craniectomy while mitigating postoperative wound complications.

Transcranial Doppler velocity and associations with delayed cerebral ischemia in aneurysmal subarachnoid Hemorrhage.

BACKGROUND AND PURPOSE: We evaluated optimal transcranial Doppler (TCD) measures for predicting delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). MATERIAL AND METHODS: Consecutive patients with aSAH and daily middle cerebral artery (MCA) TCD recordings were retrospectively analyzed. Change in TCD velocity was obtained by creating a smoothing curve. Change in TCD velocity was determined with a linear regression model that confirmed greatest change in velocity associated with DCI occurred at days 2-7. Multivariate logistic regression analysis was then completed. RESULTS: 95 patients were evaluated. Increase in TCD velocity at days 2-7 proved to be the best predictor for DCI with an optimal cutoff of 8.9 cm/s/day (p = .019) and AUC 0.651. Multivariate logistic regression analysis using DCI as outcome showed that poor admission Hunt-Hess scores (OR 5.02, 95%CI 1.22-22.67, p = .028) and increases in TCD velocity (OR 5.32, 95%CI 1.41-23.33, p = .018) were independently associated with DCI. CONCLUSIONS: We found that relative increases in TCD velocities in the MCAs during the first 7 days (with a threshold increase of 53.4 cm/s from days 2 to 7) after aSAH admission were independently associated with DCI. This association requires independent confirmation.

Intracranial hemorrhage type and same-admission mortality in patients with left ventricular assist devices.

OBJECTIVES: Left ventricular assist devices (LVAD) provide mechanical circulatory support for patients with advanced heart failure. Intracranial hemorrhage in this population represent a significant management challenge. The objective of this study is to report our initial experience on same-admission outcomes with LVAD patients that presented with various types of intracranial hemorrhage (ICH). PATIENTS AND METHODS: A retrospective review of a large volume center over a two-year period was performed. LVAD patients with ICH requiring a neurosurgical consultation were identified. Hemorrhage type, interventions, discharge disposition and cause of death were recorded. RESULTS: 27 LVAD patients with ICH received a neurosurgical consultation. The average INR at the time of ICH was 2.7 (1.0-8.8). Hemorrhage types seen were lobar (10/27, 37 %), SAH (5/27, 19 %), SDH (4/27, 15 %), cerebellar ICH (3/27, 11 %), multiple ICH (3/27, 11 %), and hemorrhagic conversion (2/27, 7 %). The overall mortality rate was 48.2 % (13/27), with the highest mortality being in those patients who had multiple ICH at the time of presentation (3/3, 100 %). The majority of patients with ICH (85.2 %) were non-operative. Lobar IPH was <3 cm in 80 % (8/10) of these, and 6/8 (75 %) ultimately died. 11 %(3/27) received surgical intervention. Of these, 67 % ultimately withdrew care. 77 % (10/13) of patients died as a result of the ICH. 80 % of patients with SAH were ultimately discharged home. CONCLUSIONS: Patients with a LVAD and ICH have a high rate of same-admission mortality (48 %). Hemorrhage location, intra-axial or extra-axial, resulted in patients being a risk for death secondary to either the hemorrhage itself or pump thrombosis, respectively.

Palliative Care Consultation and Effect on Length of Stay in a Tertiary-Level Neurological Intensive Care Unit.

Background: Patients admitted to an acute care setting with a devastating brain injury are at high risk for morbidity and mortality. These patients and their families can benefit from the psychosocial and decision-making support of a palliative care consultation. Objective: We aim to investigate the characteristics and impact of palliative care consultation for patients under the management of neurosurgical and critical care services with a devastating brain injury in a neurological intensive care unit (ICU) at a large tertiary-care hospital. Design: Data were collected by retrospective review of the electronic medical record and metrics collected by the palliative care service. Data were analyzed using descriptive statistics. Linear regression analysis was performed to assess effect of timing of palliative care consultation. Results: Fifty-five patients admitted to the neurological ICU under the management of the neurosurgical service received a palliative care consultation for the following: hemorrhagic stroke (49%), metastatic cancer (22%), and traumatic brain injury (18%). Of these, 73% had at least one neurosurgical intervention. Palliative care was most frequently consulted for assistance in defining a patient's goals of care (88%). When compared with late consultation, early palliative care consultation was significantly associated with shorter mean length of stay (LOS) and positively correlated in linear regression analysis without an effect on mortality. Conclusions: When compared with a late consultation, early palliative care consultation corresponded to shorter LOS without increasing mortality. One reason for this effect may be that palliative care can help to clarify and document goals of care earlier and more concretely.

Brain Metastases From Differentiated Thyroid Carcinoma: Prevalence, Current Therapies, and Outcomes.

BACKGROUND AND OBJECTIVE: The brain is an unusual site for distant metastases of differentiated thyroid carcinoma (DTC). The aim of this study was to document the prevalence of brain metastases from DTC at our institutions and to analyze the current therapies and the outcomes of these patients. METHODS: We performed a retrospective chart review of patients with DTC and secondary neoplasia of the brain. RESULTS: From 2002 to 2016, 9514 cases of thyroid cancer were evaluated across our institutions and 24 patients met our inclusion criteria, corresponding to a prevalence of 0.3% of patients with DTC. Fourteen (58.3%) were female and 10 (41.7%) were male. Fifteen patients had papillary thyroid cancer (PTC) (62.5%). Brain metastases were diagnosed 0 to 37 years (mean ± SD, 10.6 ± 10.4 years) after the initial diagnosis of thyroid cancer. Patients undergoing surgery had a median survival time longer than those that did not undergo surgery (27.3 months vs 6.8 months; P = 0.15). Patients who underwent stereotactic radiosurgery (SRS) had a median survival time longer than those that did not receive SRS (52.5 months vs 6.7 months; P = 0.11). Twelve patients (50%) were treated with tyrosine kinase inhibitors (TKIs), and they had a better survival than those who have not used a TKI (median survival time, 27.2 months vs 4.7 months; P < 0.05). CONCLUSION: The prevalence of brain metastases of DTC in our institutions was 0.3% over 15 years. The median survival time after diagnosis of brain metastases was 19 months. In our study population, the use of TKI improved the survival rates.

Trigeminal neuralgia treatment outcomes following Gamma Knife radiosurgery with a minimum 3-year follow-up.

OBJECTIVE: Effective short-term outcomes have been well documented for trigeminal neuralgia (TN) patients treated with Gamma Knife radiosurgery (GKRS) with reported success rates of 70-90 % with median follow-up intervals of 19-75 months. Fewer series, however, have described uniform long-term follow-up data. In this study, we report our long-term institutional outcomes in patients treated with GKRS after a minimum follow-up of 36 months. METHODS: Thirty-six consecutive patients with medically intractable TN received a median radiation dose of 45 Gy applied with a single 4-mm isocenter to the affected trigeminal nerve. Follow-up data were obtained by clinical examination and telephone questionnaire. Outcome results were categorized based on the Barrow Neurological Institute (BNI) pain scale with BNI I-III considered to be good outcomes and BNI IV-V considered as treatment failure. BNI facial numbness score was used to assess treatment complications. RESULTS: The incidence of early pain relief was high (80.5 %) and relief was noted in an average of 1.6 months after treatment. At minimum follow-up of 3 years, 67 % were pain free (BNI I) and 75 % had good treatment outcome. At a mean last follow-up of 69 months, 32 % were free from any pain and 63 % were free from severe pain. Bothersome posttreatment facial numbness was reported in 11 % of the patients. A statistically significant correlation was found between age and recurrence of any pain with age >70 predicting a more favorable outcome after radiosurgery. CONCLUSION: The success rate of GKRS for treatment of medically intractable TN declines over time with 32 % reporting ideal outcome and 63 % reporting good outcome. Patients older than age 70 are good candidates for radiosurgery. This data should help in setting realistic expectations for weighing the various available treatment options.

Meta-analysis of endoscopic versus sublabial pituitary surgery.

OBJECTIVES/HYPOTHESIS: To determine whether the endoscopic or sublabial transseptal transsphenoidal approach for pituitary surgery has superior outcomes or decreased complication rates. STUDY DESIGN: Retrospective meta-analysis of literature. METHODS: A MEDLINE search was conducted identifying all relevant literature in the English language from 1998 through 2010. Studies explicitly identifying pure sublabial or completely endoscopic approaches were included. Meta-analysis comparing the two techniques was performed for multiple outcome measures utilizing a random effects approach. RESULTS: A total of 21 endoscopic studies (n = 2,335) and 17 sublabial studies (n = 2,565) met inclusion criteria. Analysis revealed significantly superior rates of gross tumor resection (79% vs. 65%, P < .0001), as well as lower rates of cerebral spinal fluid leak (5% vs. 7%, P < .01), septal perforation (0% vs. 5%), and postoperative epistaxis (1% vs. 4%, P < .0001) for the endoscopic approach compared to the sublabial approach. There was no difference between the two techniques in the incidence of meningitis, diabetes insipidus, or resolution of hormonal abnormality. Hospital stay (P = .01) was shorter for endoscopic surgery compared to sublabial surgery, and there was no significant difference in terms of length of operation. CONCLUSIONS: The sublabial transsphenoidal approach has been the gold standard for pituitary surgery for many years. However, meta-analysis of the recent literature demonstrates superior outcomes and decreased postoperative complications with the endoscopic approach, potentially justifying a shift toward endoscopic pituitary surgery.

Risk factors for posttreatment edema in patients treated with stereotactic radiosurgery for meningiomas.

BACKGROUND: Peritumoral edema is a recognized complication following stereotactic radiosurgery (SRS). OBJECTIVE: To evaluate the risk of posttreatment peritumoral edema following SRS for intracranial meningiomas and determine predictive factors. METHODS: Between 2002 and 2008, 173 evaluable patients underwent CyberKnife or Gamma Knife SRS for meningiomas. Eighty-four patients (49%) had prior surgical resections, 13 patients had World Health Organization grade II (atypical) meningiomas, and 117 patients had a neurological deficit before SRS. Sixty-two tumors were in parasagittal, parafalcine, and convexity locations. The median tumor volume was 4.7 mL (range, 0.1-231.8 mL). The median prescribed dose and median prescribed biologically equivalent dose were 15 Gy (range, 9-40 Gy) and 67 Gy (range, 14-116 Gy), respectively. Ninety-seven patients were treated with single-fraction SRS, 74 received 2 to 5 fractions, and 2 received >5 fractions. RESULTS: The median follow-up was 21.0 months. Thirteen patients (8%) developed symptomatic peritumoral edema, with a median onset time of 4.5 months (range, 0.2-9.5 months). The 3-, 6-, 12-, and 24-month actuarial symptomatic edema rates were 2.9%, 4.9%, 7.7%, and 8.5%, respectively. The crude tumor control rate was 94%. On univariate analysis, large tumor volume (P = .01) and single-fraction SRS (P = .04) were predictive for development of posttreatment edema. CONCLUSION: SRS meningioma treatment demonstrated a low incidence of toxicity; however, large tumor volumes and single-fraction SRS treatment had an increased risk for posttreatment edema. Risk factors for edema should be considered in meningiomas treatment.